The present invention relates to sensing edges for automatic doors and, more particularly, to bilateral sensing edges which can be readily mounted on either side of the door.
Sensing edges for doors are generally well known. Such sensing edges generally include an elongate sheath in which a force sensing switch (sensor) is positioned. Upon the application of an undesired force to the sheath, the sensor actuates suitable control circuitry for controlling movement of the door. The sensor, positioned within the sheath, typically comprises a pair of flexible, electrically conductive sheets positioned on the upper and lower sides of a layer of non-conducting loam having a plurality of openings extending therethrough from the upper to the lower side. Upon application of force to the sheets, either or both of the conductive sheets are deflected into electrically conductive engagement with each other through the openings in the layer of foam, to thereby actuate suitable control circuitry for controlling the door.
The typical sensing edge includes conductors attached to the sensor for transmitting the sensing signal to appropriate control circuitry mounted to one side or the other of the door external to the sensing edge. In a typical sensing edge, the conductors exit the sheath of the sensing edge through an aperture that is located at the end surface of the sheath or on the top edge or side of the sheath.
It is very desirable for the conductors to exit from the inside of the sensor edge in order that the conductors be less susceptible to damage and to avoid interference with the door operation. However, a conventional sensing edge that employs an inside exit for the conductor requires the manufacture of both right hand and left hand versions of the sensing edge in order to properly place the conductors going to the control circuitry located on the inside of the door for both right and left handed door control circuitry installations. An additional problem may arise if an installer goes to a job site and, in the middle of an installation, discovers that for some reason the control circuitry must be located on a different side of the door than was originally planned. He must then leave the job site to exchange the sensing edge that is currently in his possession, for another sensing edge which has the conductors placed on the other side of the sensor edge.
The present invention is directed to a sensing edge for a door for sensing objects that come into contact with the sensing edge during door closing that is compatible with both right and left hand door control circuitry installations. The sensing edge in the present invention overcomes the problems inherent in the prior art by providing a means for routing the conductors to either the front side or the back side of the sensing edge after the sensing edge is completely fabricated. Although this technology is generally well known in the field, previous bilateral sensing edges require the use of a filling material to be melted into the end of the sensing edge in order to lock the conductors in place and seal the sensing edge so as to prevent damage from moisture, contaminants, and the like. The end of the sensing edge of the present invention merely requires an adhesive with which to maintain the conductors in place, allowing for easier installation than previous bilateral sensing edges. Thus, installation or changes to an installation can be made in the field by the installer without the use of tools such as a hot plate. A single model of the present sensing edge can be used for both left handed and right handed door installations, thereby eliminating the need for manufacturers to produce and stock multiple models of each sensing edge. The result is that only one item need be manufactured for both left and right handed door installations and the installer need only take a single sensing edge to the job site with the assurance that the job requirements can be satisfied, even if the installation parameters change during the installation. The ability to route the conductors to either the front side or the back side of the sensing edge makes the sensing edge bilateral.
Briefly stated, the present invention is directed to a sensing edge for actuating a device to cause a closing door having a sensing edge surface to stop closing upon a force being applied to the sensing edge. The sensing edge includes an elongated sheath positioned adjacent to the leading edge surface of the door, the sheath being compressible upon the application of an external force. The sheath forms a cavity having opposing front and rear sides and first and second oppositely disposed ends. A sensor is positioned within the cavity. The sensor is responsive to an external force applied to the sheath between the first and second ends. A closure is positioned proximate one of the first and second ends of the sheath. The closure has an outer surface facing opposite the cavity and front and rear sides corresponding to the front and rear sides of the sheath. The closure has a channel extending from the outer surface toward the cavity to a depth into the closure. The channel extends a length between the front and rear sides of the closure. The closure further includes a passageway extending therethrough from the cavity to the channel. At least one electrical conductor is in electrical communication with the sensor and extends through the passageway and partially through the channel to one of the front and rear sides.